Adding limit to webcrawler

[laura301019]

Hi I am creating a webcrawler and would like to set a limit for how many steps from the original seed can be taken, when the limit is reached the web crawler should terminate. Not sure how or where abouts to add it to my code

import urllib2

def getAllNewLinksOnPage(page,prevLinks):

    response = urllib2.urlopen(page)
    html = response.read()

    links,pos,allFound=[],0,False
    while not allFound:
        aTag=html.find("<a href=",pos)
        if aTag>-1:
            href=html.find('"',aTag+1)
            endHref=html.find('"',href+1)
            url=html[href+1:endHref]
            if url[:7]=="http://":
                if url[-1]=="/":
                    url=url[:-1]
                if not url in links and not url in prevLinks:
                    links.append(url)     
                    print url
            closeTag=html.find("</a>",aTag)
            pos=closeTag+1
        else:
            allFound=True   
    return links

toCrawl=["MyURL"]
crawled=[]
while toCrawl:
    url=toCrawl.pop()
    crawled.append(url)
    newLinks=getAllNewLinksOnPage(url,crawled)
    toCrawl=list(set(toCrawl)|set(newLinks))

print crawled   

Any help would be great.